An intervertebral disc may be subject to degeneration caused by trauma, disease, and/or aging. A degenerated intervertebral disc may have to be partially or fully removed from a spinal column. Partial or full removal of an intervertebral disc may destabilize a spinal column. Destabilization of a spinal column may alter a natural separation distance between adjacent vertebrae. Maintaining a natural separation distance between vertebrae may help prevent pressure from being applied to nerves that pass between vertebral bodies. Excessive pressure applied to the nerves may cause pain and/or nerve damage. During a spinal fixation procedure, a spinal implant may be inserted in a space created by removal or partial removal of an intervertebral disc between adjacent vertebrae. A spinal implant may maintain the height of the spine and restore stability to the spine. Intervertebral bone growth may fuse the implant to adjacent vertebrae.
A spinal implant may be inserted during a spinal fixation procedure using an anterior, lateral, or posterior spinal approach. In some situations, an anterior approach may result in an easier approach, less muscle damage, less tissue damage, and/or less bone removal than other approaches.
A discectomy may be performed to remove or partially remove a defective and/or damaged intervertebral disc. A discectomy creates a disc space for a spinal implant. After a discectomy, a spinal implant may be inserted into the disc space. One or more spinal implants may be inserted between a pair of vertebrae. Spinal implants may be inserted into disc spaces prepared between more than one pair of vertebrae during a spinal fusion procedure.
A spinal plate may be coupled to vertebrae after insertion of one or more spinal implants. A spinal plate may stabilize the vertebrae and inhibit backout of the spinal implant from between vertebrae. A spinal plate may share a compressive load applied to one or more spinal implants inserted between vertebrae. Fasteners (e.g., bone screws) may couple the spinal plate to vertebrae. Spinal plates may stabilize sections of cervical spine and/or sections of lumbar spine.
Fastening systems may attach a spinal plate to vertebrae without allowing fasteners of the fastening systems to back out from the vertebrae. A fastening system may include a fastener and a retainer. The retainer may be positioned in an opening of the spinal plate. Backout of fasteners from the spinal plate may be inhibited without immovably fixing the fasteners or the retainers to the spinal plate. U.S. Pat. No. 6,331,179 to Freid et al. and U.S. Pat. No. 6,454,679 to Wagner et al., both of which are incorporated by reference as if fully set forth herein, describe bone plate systems including fasteners and retainers.
U.S. Pat. No. 6,328,738 to Suddaby, which is incorporated by reference as if fully set forth herein, describes an anterior cervical fusion compression plate and screw guide. The anterior cervical fusion compression plate has a pair of slideable inserts. Each insert is situated in a recess at an end of the plate to allow vertebral compression. During an insertion procedure, a pliers-like tool is used to move the inserts toward the center of the plate. After a desired compression is achieved, central screws are tightened to fix the position of the inserts. Lateral screws may be driven into the inserts to anchor the vertebrae to the plate.